Radioimmunoassay of somatostatin: methodological problems and physiological investigations

Somatostatin, a tetradecapeptide, has a wide distribution throughout the central nervous system and the gastrointestinal tract and a broad spectrum of biological actions. In order to investigate its various physiological roles in man, a radioimmunoassay was developed for somatostatin in human blood plasma, which is described here. This RIA was used to investigate possible factors influencing somatostatin secretion. Changes in somatin levels produced by changes in insulin, glucagon and growth hormone levels were studied via the response of plasma immunoreactive somatostatin to hormonal stimuli in normal man. The influence of fasting and food consumption was studied; and the site of origin of circulating immunoreactive somatostatin was investigated in patients. (Auth.)